A plasma dicing apparatus in which a semiconductor wafer with a protective sheet stuck thereonto covering the entire circuit-forming surface and with an etching-resistant mask member stuck on the back surface opposite to the circuit-forming surface is mounted on a mounting stage; plasma etching is performed using the mask member as a mask; and the semiconductor wafer is diced into plural semiconductor chips. The plasma dicing apparatus includes a ring-shaped frame member retaining the outer circumference of the mask member extending off the outer circumference of the semiconductor wafer. The mounting stage is composed of a wafer supporting part supporting a semiconductor wafer and a frame member supporting part supporting the frame member. This facilitates carrying a semiconductor wafer into and out of the vacuum chamber.